Brake



E. V. TAYLOR April 10, 1934.

BRAKE 5 Sheets-'Sheet l 9 @Ey/l Filed April 2l, 1930 fra? 5 Sheets-Sheet 2 BRAKE E. V. TAYLOR Filed April 2l, 1930,

April 1o, 1934.

n 17, MDW 0 0 f5 h 522 (ff-@gw April 10, 1934. E. v. +AYLQR 1,953,996

BRAKE Filed April 2l, 1930 5 Sheets-Sheet 3 ZbW/92%)? Patented Apr. 1i), 1934 @FFIC BRAKE Eugene V. Taylor, Chicago, Ill.

Application April 21, 1930, Serial No. 445,933

Claims.

This invention relates to braking mechanisms, and more particularly to such a mechanism as will be self-pressure acting, for use on motor vehicles, buses, railway cars, aeroplanes, etc.

The main feature of the present invention resides in the provision of a novel braking mechanism including novel structural characteristics of simple and durable construction which will be self-energizing and self-pressure acting. To this end I have provided a braking mechanism comprising sectionalized shoe means adapted to be associated internally of a rotatable drum and including expanding means normally urging the shoe means in engagement with the usual annular braking surface of the drum, whereby the shoe means partakes of the rotary movement of the drum in inoperative condition. A rotatable collar is associated. with the shoe means and has a floating action with respect thereto, the collar being also adapted to partake of the rotary motion of the drum in inoperative condition. The usual backing plate of the brake mechanism assembly is provided with a stationary member which acts as a bearing support for the rotatable collar.

This stationary member is provided with a suit able clutching member in the nature of a flying key preferably', the latter being adapted to selectively take into any one of a series of annular notches provided in the rotatable collar. Thus, when the key is permitted to take into any one of the notches of the rotating collar, the collar is immediately restrained from rotational movement turn restraining` rotational movement on the part of the shoe means whereupon braking action is applied to the drum to retard the rotation thereof. .Due to the employment of section-f` alized shoe means normally yieldingly expanded for engagement with the drum, the yieldable expanding to initially reduce the effective braking action of the shoe means and then gradually increases the effective brake pressure between the shoe means and the drum thereby gradually retarding the rotation of the drum until the pressure of the shoe means is restored to maximum condition.

The above briefly described braking mechanism is particularly applicable to light vehicles. In the case of heavier vehicles it is desirable to produce a progressive braking action will be well understood by those skilled in the art. To accomplish this latter feature, l have provided a novel braking mechanism wherein I employ a plurality of coaxially disposed brake shoe means each of the general character above outlined. To produce progressive braking effect in such a construction, I have provided certain novel structural features whereby each of the coaxially disosed shoe means is adapted t0 be successively operated thereby producing the desired progressive braking effect. 39

A further feature of importance resides in the provision of sections of brake shoe means which are reversible and interchangeable so that when a section as is subjected to more wear than its component section, the sections may be readily interchanged to obtain maximum efciency and use from the shoe means. Then again in the case of a plurality o axially disposed shoe means several of the shoe means may be subjected to considerable wear while others may receive very little wear. It will be readily apparent that under such conditions interchangeability of the shoe means sections is a desirable and important feature.

Other and further features of importance and advantages will appear from a following detailed description of several preferred embodiments of my invention illustrated in the accompanying drawings in which:

Figure l is a transverse section through a brake drum embodying the salient features of the improved braking mechanism, the section being taken substantially along the line l-l of Figure 2;

Figure 2 is a section taken along the line 2-2 of Figure l;

Figure 3 is a fragmentary rear elevation of the backing plate illustrating the operative position of the operating cam lever;

Figure 4 is a section showing a modined form of operating means;

Figure 5 is a section similar in character to that illustrated in Figure 2 and showing a modi fied form of braking mechanism providing for progressive braking eect;

Figire 6 is an elevation oi the operating means illustrated in Figure 5; 5

Figure 7 is a View similar to that shown in Figure 2 illustrating a further modified form of braking mechanism for progressive braking action; and

Y Figure 8 is a further modified form of control means for a braking mechanism of the character illustrated in Figure 7 showing more or less diagrammatically the important features thereof.

Referring now more particularly to Figures l 'to 3 inclusive, I have illustrated a brake drum l0 suitably secured to the spokes of a wheel ll as by means of bolts such as 12. Drum l0 is preferably provided at its open end with an offset flange 13 in which is confined the usual backing plate 14 to provide an enclosure to which mud, dirt and the like will not have ready access.

A brake shoe means comprising sections 15 and 16 of substantially U-Shaped cross section each provided on the outer side of the web portion with suitable brake lining 17 and 18, respectively, are positioned in the brake drum in opposedrelation to each other with the brake lining of each in engagement with the inner periphery of the fiange of brake drum 10. At one end, each of sections 15 and 16 is provided with an inward- 1y projecting member 19 having its base 20 suitably secured to the inner side of the web of the section and having a radially inwardly extending portion 2l provided with a seat 22 and at its extreme inner end with a lug 23. A coil spring 24 is seated with its ends in seats 22 and normally exerts pressure against the ends of sections 15 and 16 in opposed directions thereby normally urging the sections into engagement with the braking surface of the drum 10.

At the other ends, sections l5 and 16 are each provided with a similar member 25 having its base or supporting portion 26 suitably secured to the web portion of the section and inwardly directed portion 27 providing a seat 28. A coil spring 29 has its ends suitably seated in seats 28 to normally exert pressure against the seats 28 in opposed relation thereby normally urging sections 15 and 16 into engagement with the braking surface of the brake drum 10.

Springs 24 and 29 are of such resiliency as to urge sections 15 and 16 into such frictional engagement with the braking surface of the drum 10 that in inoperative condition, these sections will normally partake of the rotary movement of the brake drum.

Concentrically disposed and secured to the inner side of the backing plate 14 is a stationary ring 30. Ring 3G preferably comprises an annular laterally extending spacing portion 31 and an annular bearing portion.

A rotatable ring 33 has its inner periphery seated upon the annular portion 32 for bearing support thereon and is provided with a series of radially disposed notches 34 extending from the inner periphery thereof. An enlarged radially outwardly extending lug 35 is positioned for oating movement in notches or slots 36 provided in lugs 23. Lug 35 preferably has a greater radial depth to the right thereof as viewed in Figure 1, to provide more substantial body thereto for cooperation with the end wall of the associated notch or slot, since braking effect of the wheels of a moving vehicle is applied more frequently to retard forward movement of the vehicle than rearward movement. This provides greater body for the lug 35 where the most wear and transverse stress are apt to occur. In opposed relation to lug 35, ring 33 is provided with parallel spaced guide lugs such as 37 which serve as guide means for members 25 of the sections 15 and 16.

It will be at once apparent that ring 33 due to its floating connection with shoe sections 15 and 16 will have rotary movement about its support 30 so that ring 33 will similarly partake of the rotary movement of the brake drum 10 in the inoperative condition of the braking mechanism.

Ring 30 is provided at one portion thereof with a radially inwardly extending projection 38. Projection 38 is provided with an open portion 39 in the nature of a housing, opening 39 extending laterally through the annular lateral portion 31 to the backing plate 14. Adjacent the backing plate 14 and depending from the upper wall of opening 39 is a U-shaped bracket 40 suitably secured to such Wall by means of a bolt 41. A bolt or flying key 42 of substantially L-shaped configuration is pivotally mounted between the legs of the bracket 40 upon a pin 43. The underside of the inner end of key 42 is provided with two seats 44 and in opposed relation thereto the bottom wall of opening 39 is likewise provided with two seats 45. A pair of coil springs 46 have their respective ends seated in seats 44 and 45 to normally urge the clutching end 47 of the key 42 radially outwardly of the ring 30 in the direction of notches 34 of rotary ring 33. The opposite end of key 42 is provided with a reduced journal portion 48 extending outwardly through a vertically disposed slot 48 in backing plate 14 and beyond the outer face thereof, a spherical roller 49 being journaled on portion 48 and suitably retained from removal therefrom by means of a bolt 50.

An operating lever 51 is pivotally mounted upon a bolt 52 positioned on the outer side of the backing plate 14, bolt 52 being disposed between lateral portion 31 of the ring 30 and the axis of the plate 14. Intermediate its ends, lever 51 is provided with an angularly disposed slot 53 in which roller 49 is adapted to ride and the outer face of the slotted portion of lever 51 is provided with a suitable cover plate 54. The upper end of lever 51 is offset and is provided with an enlargement 55 having a perforation or hole 56 therein. A iiexible cable 57 has one end thereof passed through perforation or hole 56 and is suitably anchored by means of an anchor 58 at this end. The other end of cable 57 may extend to a suitable central control such as a foot pedal or other suitable means to impart swinging movement to lever 51. A coil spring 59 has one end thereof suitably anchored in lever 51 with the other end thereof suitably anchored in backing plate 14 to normally urge the lever 5l to inoperative condition.

A cover plate 60 (see Figure 2) may be provided for the inner edge of stationary ring 30, and may be suitably secured thereto.

In operation, shoe sections 15 and 16 in inoperative condition partake of the rotary motion of the brake drum 10, rotatable ring 33 likewise partaking of such rotary action due to its oating connection with sections 15 and 16. In inoperative condition of the braking mechanism, spring 59 is sufciently strong enough to urge lever 51 to the left as viewed in Figure 3 whereupon cam slot 53 will maintain the projecting end of key 42 in elevated position with the clutching end 47 of key 42 being withdrawn downwardly into the open portion 39 of ring 30. When it is desired to produce braking effect upon the drum 10, lever 51 is moved to the right as viewed in Figure 3 against the tension of spring 59. At this time, springs j? 46 will aid cam slot 53 in urging the clutching end 47 of key 42 upwardly causing the clutching end 47 of key 42 to take into one of the notches 34. Assuming the drum to be rotating in a direction of the arrow in Figure l, as soon as key 42 becomes engaged in one of the notches ring 33 will be restrained from rotary motion. At this time lug 35 will engage the lug 23 of shoe section 16 thereby restraining section 16 from rotation.

Section 16 will therefore immediately impose a 1 braking action upon the brake drum 10 but of itself will not produce a sufficient braking action between brake drum 10 and its brake lining to completely retard and overcome rotation of drum 10. Concurrently with the initial clutching enga'genent of key 42, shoe section 15 will tend to continue to rotate with drum and this rotation will be partially aided by spring 24 but will be opposed by spring 29. Thus, the maximum braking effect possible of the combination oi shoe sections and 16 is then attained.

As the eiiect of the braking action of shoe section 16 is imposed upon the drum, simultaneously shoe section 15 will be energized by the rotating `drum due to the frictional contact and the force exerted by spring 24 upon the end oi the shoe. This energization of shoe 15 will be continuous while the drum is rotating, and the force thus derived will be transmitted by shoe 15 to the shoe 16 through spring 29, or by direct contact of the shoe ends, if the derived force is greater than the force of spring 29. The position or" shoe 15 will depend upon the force of the springs 24 and 29, and shoe 15 may return to its initial biased position before the drum stopped from rotating if the spring 29 has greater force than the frictional force derived from the contact of shoe 15 with the drum.

Thereaction point being inwardly from the drum, shoe section 16 at its end base member 19, will be wedged between 'the reaction point and the drum; this wedging action is the first braking eifect derived at the moment the key 42 is in enl gagement with ring 3o. The second braking effeet will appear as shoe 16 will be urged by the resultant force to turn about the reaction point as fulcrum and a high pressure area will be established near end oi shoe 16 at member 25. This high pressure area on shoe 16 will receive further force from the kinetic energy oi shoe 15 and all its component parts acting through spring 29. As soon as spring 29 reacts on shoe 15, this shoe will be energized by the drurn and the iorce tending to rotate shoe 15 in the direction of the arrow, is transmitted to spring 29 and then to shoe 16. At this moment maximum braking eiiect is derived. The braking effect changes gradually according to the applied force, but will never be less than what is iixed by the springs 24 and 29, in exerting tangential pressure upon the shoes 15 and 16.

The braking action is therefore variable from a fixed level to a maximum level, and then back to a point which is equal to said xed level plus the self energizing action received from the brake drum.

It will be at once apparent that upon rotation of the drum 10 in the opposite direction, the action will be reversed, lug engaging the lug 23 of shoe section 1.5 whereupon shoe section 15 will be restrained from movement, section 16 in this case providing the gradual control of braking eirect.

In Figure 4, I have illustrated a modified form of operating means. 1n this case, a casing 61 providing a slot or guideway 62 is suitably secured to the outer face of backing plate 14 with the open side of guideway 62 against such outer face and superimposed upon the portion provided with slot 48. A corresponding and coincident slot 63 is provided in the base or supporting portion of casing 61 for the passage therethrough into guideway 62 of the roller 49 of key 42. Preferably, in the employment of the modified form of operating means herein referred to, springs 46 are omitted whereupon clutching end 47 which is rather heavy compared to the operated end or" key 42 will be normally gravity urged downwardly to inoperative or declutched condition. A slide 64V is positioned in the guideway 62 for reciprocating movement therein, a horizontally disposed transverse trapezoidal slot 65 providing an angularly disposed camming shoulder 66 being formed therein opening downwardly. The outer end of slide 64 comprises a reduced portion 67 having an upwardly extending right-angularly disposed lug or projection 68 at its extreme end. Casing 61 an extension 69 at its end providing an extension or guideway 62, the end wall 70 which acts as a stop for the outer end o1 slide 64. A coil spring 71 is interposed between the shoulder 'Z2 or" slide 64 and end wall 70 to normally urge slide 64 to inoperative condition. A cable 73 has one end thereof passing through a perioration 74 in projection 68 and a suitable anchor 75 secured to this end or" cable 73 is adapted to engage projection 68 in the operating direction or movement of cable 73. The opposite end ci cable 73 may be connected with an operating control means 'such as a foot pedal for effecting or imposing reciprocation upon cable 73.

As will be readily apparent, in the inoperative condition of a braking mechanism of the character disclosed in Figures 1 3 inclusive, key 42 will have its operated or roller provided end in raised position as indicated in dotted lines in Figure 4. Normally, in inoperative condition of such a braking mechanism slide 64 will be disposed with its left end abut-ting the left end wall of guideway 62. Thus in such inoperative condition, groove 65 will be disposed with its deepest portion in alignment with slot 48. Thus, when cable 73 is drawn to the right, anchor 75 will engage projection 68 causing retraction of slide 64 against the pressure or" coil spring 7l. Thereupon, cam shoulder 66 engages roller 49 depressing the corresponding end or key 42 and elevating the clutching portion 47 thereof for engagement with one of the notches 34 causing braking of drum l0 in a manner hereinbeore more fully described. Upon release of cable 73, spring 71 will urge slide 64 to the left, causing realignment or" groove 65 with slot 48 and consequent release oi key 42 to inoperative condition. As will be observed from the foregoing, the parts illustrated in Figure 4 have been shown in the operative condition of the braking mechamsm. l

The hereinbefore described braking mechanism and operating means are particularly applicable to light vehicles. In the case of heavier vehicles, it is desirable to pro-vide greater braking surface and to employ progressive braking action. To this end, I have provided modified forms of braking mechanisms illustrated in Figures 5 to 8, inclusive.

Referring more particularly to Figures 5 and 6, the braking mechanism therein illustrated is mounted for association with a brake drum .and backing plate 81 substantially in the manner of the hereinbefore described mechanism. In this case, however, the mechanism comprises a plurality of sectionalized shoe means 82, 83 and 84 disposed in coaxial alignment within the drum 80, each comprising the usual lining 85 each being provided with radially inwardly extending projections 86, 87 and 88 respectively. Projections 86, 87 and 88 are each provided with suitable seats 89 in which coil springs 90 are adapted to be seated as in the case of modification disclosed in Figures l to 3, inclusive. Each of portions S6, 87 and 88 are further provided with depending lug portions 91, 92 and 93, respectively, providing suitable seats 94, 95 and 96, respectively.

A suitable stationary ring 97 having an inner cover plate 98 suitably secured thereto is secured to the backing plate 8l in any suitable or desired ist lso

manner, ring 97 being provided with an open portion 99. A bracket 100 secured to the outer face of backing plate 81 pivotally supports a swinging lever or key 101 at 102, the inner end of key 101 being adapted to be normally spring projected upwardly by means of a coil spring 103. The outer end of key 101 is provided with a reduced bearing portion 104 which carries journaled thereon a spherical roller 105 suitably retained thereon by means of a bolt 106 threaded into the reduced portion 104.

A plurality of rotatable rings 107, 108 and 109 are suitably mounted for bearing movement about stationary ring 97, each of these rings is provided with an outwardly projecting lug 110, 111 and 112, respectively, which are adapted to take into the groove or recesses 94, 95 and 96, respectively. Ring 107 is of greater radial transverse section than ring 108, the latter being in turn of greater radial transverse section than ring 199. Each oi the rings is provided with radial notches 113, 114 and 115, notches 113 being deeper than notches 114 and the latter being deeper than notches 115.

Th outer side of the backing plate 81 carries suitably pivoted upon a pin 116 a cam lever 117 provided with an eccentric camming portion 118 upon which roller 105 of key 101 is adapted to ride. A coil spring 119 serves to normally urge the cam lever 117 to inoperative position being of suicient strength to normally overcome the projecting power of spring 103. A suitable ilexible cable 120 has one end thereof suitably anchored in the end of cam lever 117 in opposed relation to the spring 119, the other end of cable 120 being suitably secured to a control means readily accessible to an operator of the vehicle to which the braking mechanism is applied.

In operation, shoe means 82, 83 and 84 are normally adapted to partake of the rotary movement of brake drum 80, rings 107, 108 and 109, partaking of such rotary motion also, due to the connection thereof with shoe means 82, 83 and 84. In inoperative condition, key 101 is normally in the position illustrated in dotted lines in Figure 5, being retained in this condition by the engagement of the camming portion 118 of cam lever 117, which is drawn to the left as illustrated in Figure 6 by the coil spring 119.

When it is desired to energize the braking mechanism, as the cam lever 117 moves to operative position as illustrated in Figure 6, key 191 will rst take into one of the notches 113 in ring 107. Upon further movement of cam lever 117 to the right, one of the notches in ring 108 will be engaged, thereby adding the braking effect of shoe means 83 to the already energized shoe means 82. If additional braking effect is desired, upon movment of the cam lever 117 to maximum position, key 101 will be further urged upwardly to clutch with one of the notches in ring 109, thus adding the braking effect of shoe means 84 to the already acting shoe means 82 and 83.

Referring now more particularly to Figure 7, I have illustrated another modified form of multiple progressive braking mechanism. In this case the braking mechanism is associated with a brake drum 121 and backing plate 122', frictional shoe means 123 and 124 being disposed in coaxial alignment with the axis of the drum 121. Backing plate 122 is secured to the axle housing 131 in any suitable or desired manner. Shoe means 122 is provided with a radially inwardly extending projection 124 encasing a plurality of coil springs 125, adapted to expand the sections of the shoe means into engagement with the braking surface of drum 121. Similarly, shoe means 123 is provided with a radially inwardly extending projection 128 providing a housing for a plurality of coil springs 127. Projection 124 is provided at its extreme inner end with a seat 128, while projection 126 is similarly provided with a seat 129. A stationary ring 130 is suitably secured to the backing plate 122 as by means of bolts, such as 131 and is provided at its uppermost portion with a plurality of radial guideways 132 and 133. A rotatable ring 134 is suitably supported for rotation by stationary ring 130, with its inner periphery adapted to pass over the guideway 132. Similarly, a rotatable ring 135 is carried by stationary ring 130 with its inner periphery adapted to pass over the guideway 133. Rings 134 and 135 are provided with radially outwardly extending projections 136 and 137, respectively, adapted to take into grooves or recesses 128 and 12 respectively of shoe means projections 124 and 126, respectively.

A radially sliding key 138 is guided in guideway 132 and is normally spring projected by means of coil spring 139. Similarly, a key 140 is guided for sliding movement in guideway 133 and is adapted to be normally urged radially outwardly in the guideway by means of a coil spring 141.

An operating rod 142 is mounted for transverse sliding movement in a guideway 143 and is provided with a head 144 at its outer end, this end being disposed beyond the outer face of backing plate 122. A coil spring 145 is disposed between the head 144 and backing plate 122 to normally urge operating bolt or slide 142 which is provided witb two camming portions 146 and 147, adapted to engage bolts or keys 138 and 140, respectively, to draw them downwardly against the pressure of springs 139 and 141, respectively.

Camming portions 146 and 147 are so spaced apart that upon movement of the slide 142 to the left against the pressure of spring 145, cam surface 147 will engage its sliding key 140 before cam surface 146 will engage its corresponding sliding key 138.

Rings 134 and 135 are provided with radial notches 148 and 149, respectively, into which the ends of keys 133 and 140 are adapted to take, respectively.

A lever 159 is suitably pivotally supported on backing plate 122 by means of a bolt 151, lever 130 being provided at one end with a camming surface 152, against which the outer face of head 144 is adapted to abut.- The opposite end of lever 150 is provided with a suitable eye 153, through which one end of an operating cable (not shown) may be passed and suitably anchored to provide for an operating connection with some control means positioned for ready accessibility by an operator of a vehicle so equipped.

It is to be noted that coil spring 145 is sufficiently strong to so engage camming surface 152 that the lever 150 will normally be returned to inoperative controlling condition.

In operation, shoe means 122 and 123, and rings 134 and 135 are adapted to normally rotate with brake drum 121 in inoperative condition. In inoperative condition, enlarged portions 154 and 155 of slide 142 will normally retain the keys 138 and 14()v in retracted condition out of engagement with the respective notches 148 and 149. When it is desired to effect braking condition of the shoe means 122 and 123, slide 142 is permitted to be retracted to the right as viewed in Figure 7 due to the pressure of coil spring 145, at which time cam portion 146 will disengage from its respective key 138 permitting this key to take into one of the notches 148 of its respective ring 134. Thus shoe means 122 will be initially energized. As soon as slide 142 is permitted to be further retracted to the right as viewed in Figure 7, whenV cam portion 14.7 leads its respective key 140 free to be urged upwardly by its coil spring 141, shoe means 123 will then become effective to provide additional braking effect upon drum 121. Thus it will be seen that a simple operation on the part of an operator of the vehicle will produce successive operation of the shoe means 122 and 123 thus insuring of progressive braking effect upon the brake drum 121.

Referring now more particularly to Figure 8, I have illustrated in more or less diagrammatic form a further modified form of the braking mecha-- nism embodying the salient features of the presn ent invention. Projections 166 and 161 are similar in character to projections 124 and 126 illustrated in Figure 7, and each of these is provided with a suitable groove or depression 162 and 163 respectively, each being further adapted to house a coil spring 164 to normally urge the respective shoe means into engagement with the usual brake drum. The usual rotatable rings 165 and 166 are each provided with upstanding projections or lugs 167 and 168 respectively which are adapted to take into the respective grooves or recesses 162 and 163. Each of the rings 165 and 166 is provided upon the inner annular surface with suitable notches 169 and 170 respectively.

The flying keys in this case comprise two slidable members 171 and 172 normally urged to operative condition by means of coil springs 178 and 174 respectively. Each of these keys 171 and 172 is provided with notches 175 and 176 respectively providing cheaper portions which are adapted to be engaged by the hooked ends of swinging levers 177 and 178 respectively suitably pivoted at 179 and 180 respectively and being normally in the direction of keys 171 and 172 respectively by coil springs 181 and 182 respectively.

An operating slide 183 is provided with projections 184 and 185 which are adapted to successively engage bolts or levers 177 and 178 respectively upon sliding movement thereof to the right as viewed in Figure 8. Y

In normally inoperative condition of the braking mechanism, flying keys 171 and 172 are normally retained in depressed or retracted condition by the levers 177 and 178 permitting rings 165 and 166 to freely rotate with the respective shoe means. Upon movement of the rod or vslide 183 to the right as viewed in Figure 8, lug or projection 184 will first release lever 177 whereupon its corresponding flying key 171 will take into one of the notches 169 in ring 165 thereby restraining it from rotation and consequently pern mitting energization of its respective shoe means to effect braking action upon the usual brake drum. Upon continued movement of the rod 188 to the right lug 185 will engage its lever 178 and cause it to release its corresponding slide or ilying key 172 for engagement with one of the notches 170 in ring 166, thereby causing energization of its respective shoe means.

While I have disclosed the various modified forms of the present invention as employing a mechanical operating connection, such, for eX- ample, as a cable, it will be readily apparent that any other suitable operating means may be ernplo-yed.

While 1 have disclosed several preferred embodiments of my invention, it will be understood that I do not wish to be limited thereto. As Will be apparent to those skilled in the art, certain changes other than those above noted may be made therein Without departing from the essence of the invention or the spirit and scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

l. A self-energizing braking mechanism comprising a rotatable drum, shoe means within said drum and adapted to partake of the rotation thereof, and means adapted to restrain rotation of said shoe means thereby retarding rotation of said drum.

2. A self-energizing braking mechanism comprising a rotatable drum, shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means to restrain rotation of said shoe means thereby retarding rotation of said drum.

3. A self-energizing braking mechanism comprising a rotatable drum, yieldable shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means to restrain rotation of said shoe means thereby yieldingly retarding rotation of 105 said drum.

4. A self-energizing braking mechanism comprising a rotatable drum, yieldable shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means to restrain rotation of said shoe means thereby yieldingly retarding rotation of said drum, said floating means including a provision 1'15 for selective coaction with said last named means'.

5. A self-energizing braking mechanism comprising a rotatable drinn, shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means to restrain rotation of said shoe means thereby retarding rotation of said drum, said shoe means including means for initially absorbing shock in- 125 cident to the coaction of the last named means and floating means.

6. 'A self-energizing braking mechanism comprising a rotatable drum, shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means to restrain rotation of said shoe means thereby retarding rotation of said drum, said shoe means including means for initially absorbing shock ine cident to the coaction of the last named means and floating means and for reducing initial braking effect of said shoe means.

7. A self-energizing braking mechanism comprising a rotatable drum, shoe means associated with said drum and adapted in inoperative condition to partake of the rotation thereof, floating means associated with said shoe means, and means adapted to coact with said floating means 145 to restrain rotation of said shoe means thereby retarding rotation of said drum, said shoe means including means initially absorbing shock incident to the coaction of the last named means and floating means, concurrently reducing initial braking effect of said shoe means and gradually increasing the braking action of said shoe means to maximum braking effect.

8. A self-energizing braking mechanism comprising a rotatable drum having an annular braking surface, sectional shoe means Within said drum, means for maintaining said shoe means in engagement with said surface whereby said shoe means partakes of the rotary movement of said drum, and means adapted to restrain rotation of said shoe means thereby restraining rotation of said drum.

9. A self-energizing braking mechanism comprising a rotatable drum having an annular braking surface, sectional shoe means associated with said drum, expanding means for maintaining said shoe means in engagement with said surface whereby said shoe means partakes of the rotary movement of said drum in inoperative condition, floating means associated with said shoe means, and means adapted to engage said floating means to restrain rotation of said shoe means thereby restraining rotation of said drum.

10, A self-energizing braking mechanism coinprising a rotatable drum having an annular braking surface, sectional shoe means associated with said drum, expanding means for maintaining said shoe means in engagement with said sur-face whereby said shoe means partakes of the rotary movement of said drum in inoperative condition, fioating means associated with said shoe means, and means adapted to engage said oating means to restrain rotation of said shoe means thereby restraining rotation of said drum, said expanding means being effective to initially reduce the braking effect of said shoe means and to gradually increase the braking action thereof to maximum.

11. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar having connection with said shoe means and partaking of the rotary motion of said drum, and stationary means including means for engaging said collar and restraining rotation thereof whereby said shoe means will be effective to retard rotation of said drum.

12. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means parta-kes of the rotary movement of the drum, a collar including selectively engageable means and having connection with said shoe means whereby said collar partakes of the rotation of the drum, and stationary means including means for engaging said Sele"- tively engageable means for restraining rotation of the collar whereby said shoe means will be effective to retard rotation of said drum.

13. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar having connection with said shoe means and partaking of the rotary motion of said drum, and stationary means including means for engaging said collar and restraining rotation thereof whereby said shoe means will be effective to retard rotation of l said drum, said expanding means being effective to initially aid in reducing braking effect of the shoe means and to gradually increase the braking action thereof to maximum.

14. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar including selectively engagea-ble means and having connection with said shoe whereby said collar partakes of the rotation of said drum, a stationary support upon which said collar is rotatable, and means carried by said support for engaging said selectively engageable means for restraining rotation of said collar whereby said shoe means will be effective to retard rotation of said drum.

15. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the rum, a collar having connection with said shoe means and adapted to partake of the rotation of said drum, a plurality of selectively engageable notches in said collar, a stationary member upon which said collar has bearing support, and means carried by said member and adapted to be selectively engaged in said notches for restraining rotation of said collar whereby said shoe means will be effective to retard rotation of said drum.

16. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar having connection with said shoe means and adapted to partake of the rotation of said drum, a plurality of selectively engageable notches in said collar, a stationary member upon which said collar has bearing support, and a flying key carried by said member and adapted to have selective engagement in said notches for restraining rotation of said collar whereby said shoe means will be rendered effective to retard rotation of said drum.

17. A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar having connection with said shoe means and adapted to partake of the rotation of said drum, a plurality of selectively engageable notches in said collar, a stationary member upon which said collar has bearing support, a movable normally spring pr jected key for selectively engaging said notches for restraining rotation of said collar whereby said shoe means will be rendered effective to retard rotation of the drum, and means controlling the effective position of said key.

18, A self-energizing and self-pressure action brake comprising a rotatable drum, sectional shoe means, expanding means to normally maintain said shoe means in engagement with said drum whereby the shoe means partakes of the rotary movement of the drum, a collar having connection with said shoe means and adapted to partake of the rotation of said drum, a plurality of selectively engageable notches in said collar, a stationary member upon which said collar has bearing support, a movable normally spring projected key for selectively engaging said notches for restraining rotation of Vsaid collar 'whereby said shoe means will be rendered effective to re1- tard rotation of the drum, and cam means controlling the effective position of said key.

19. A self-energizing brake mechanism comprsing a rotary drum, a plurality of expansible internal shoe means associated with said drum and partaking of the rotation thereof, internal ilying key means adapted to successively restrain rotation of said shoe means whereby rotation of the drum is progressively retarded.

2). A self-energizing braise mechanism comprising a rotary drum, a plurality of expansible internalishoe means associated with said drum and partaking of the rotation thereof, internal flying key means adapted to successively restrain rotation of said shoe means whereby rotation of the drum Ais progressively retarded and means controlling the effective positions of said means.

A self-energizing brake mechanism cornprising a rotary drum, a plurality of shoe :means associated with said drum and partaling of the rotation thereof, means adapted to successively restrain rotation ci said shoe means whereby rotation of the drum is progressively retarded., and means including a lost motion connection for controlling the successive eiiective positions of said means.

22. A self-energizing braking mechanism comprising a rotatable drum, a plurality or brake shoe means associated with said drum and partalring of the rotation thereof, a plurality of rotatable collars having connection with said brake shoe means, a stationary member upon which said collars have bearing support, a plurality of slidable means adapted to have selective engagement with said collars, and control means for controlling the effective positions oi said slidable means, said control means including means for successive response of said slidable means whereby said shoe means are successively restrained from rotation thereby progressively retarding rotation of said drum.

23. A self-energizing braking mechanism comprising a rotatable drum, a plurality of brake shoe means associated with said drum partaliing of the rotation thereof, a plurality of rotatable collars having connection with said brake shoe means, a stationary member upon which said col lars have bearing support, a plurality of slidable means adapted to have selective engagement with said collars, and control means for controlling the effective positions of said slidable means, said control means including lost motion means for successive response of said slidable means whereby said shoe means are successively restrained frornrotation thereby progressively retardlng rotation of said drum.

2li. A self-energizing braking mechanism comprising a rotatable drum, a plurality or" bra`-e shoe means associated with `said drum and partaking of the rotation thereof, a plurality of rotatable collars having connection with said brake shoe means, a stationary member upon which said collars have bearing support, a plurality of slidable means adapted to have selective engagement with said collars, and control. means or controlling the effective positions oi said slidable means, said reciprocable control means including means for successive response of said slidable means whereby said shoe means are successively restrained from rotation thereby progressively retarding rotation of said drum.

25. A self-energizing braking mechanism. comprising a rotatable drum, a plurality ci brake shoe means associated'with said drum and partaking of the rotation thereof, a plurality of rotatable collars having connection with brake shoe means, a stationary member upon which said collars have bearing support, a plurality of slidable means adapted to have selective engagement with said collars, control means for controlling the effective positions oi slidable means, said control means including means for successive response oi said slidable means whereby said shoe reans are successively restrained from rotation thereby progressively reta-rding rotation of said drum, and operating means effecting selective positioning oi said control means.

2e. A self-contained pressure braking mechanism comprising a rotatable drum, brake shoe means within. said drum and rotatable with said drum, expanding means urging said shoe means into engagement with said drum, means associated with said shoe means and rotatable therewith, and means adapted to stop rotation of said last named means whereby said shoe means is rendered effective to decelerate the rotation of said drum.

27. A self-contained pressure braking mechanism comprising a rotatable drum, brake shoe means within said drum, expanding means urging said shoe means into engagement with said drum rendering said shoe means rotatable with. said drum, a rotatable control ring means associated with said shoe means, and means cooperaile with said ring to stop the rotation of said ring means whereby said shoe means are stopped, thereby decelerating the rotation of said drum.

28. A self-contained pressure braking mechanism comprising a rotatable drum, brake shoe means within said drum, spring means under compression interposed between the ends of said shoel means and urging saidshoe means into engagement with said drum rendering the shoe means rotatable with said drum, a revolving control ring means associated with said shoe means, and a locking means for said ring means whereby shoe means is stopped from rotation with said drum thereby decelerating the rotation of said drum.

29. A self-contained pressure braking mechanlsm comprising a rotatable drum, brake shoe means including a plurality of sectional shoes positioned end to end within said drum, spring means under compression between the ends or' the sectional shoes urging said shoe means into engagement with said drum rendering the shoe means normally rotatable with the drum, a rotatable control ring means associated with said shoe means and normally rotatable therewith, and a locking means cooperable with said ring inea-ns and which may be rendered effective to stop ring means whereby the shoe means is stopped from rotation with said drum, thereby deceierating rotation oi said drum.

30. A self-contained pressure braking mechanisrn comprising a rotatable drum, brake shoe means including a plurality of interchangeable sectional shoes positioned end to end within said drum, spring means under compression between the ends of the sectional shoes urging said shoe means into engagement with said drum rendering the shoe means normally rotatable with the drum, a rotatable control ring means associated with said shoe means and normally rotatable therewith, and a locking means cooperable with said ring means and which may be rendered effestive to stop said ring means whereby the shoe means is stopped from rotation with said drum, thereby decelerating rotation of said drum.

31. Braking mechanism comprising a rotatable member, resiliently expansible internal shoe means normally rotatable with said member, internal ying key means adapted to restrain rotation of one of said shoe means whereupon said last named shoe means imposes braking effect upon the rotatable member, another of said shoe means being automatically responsive to impose cumulative braking effect upon said member.

32. Braking mechanism comprising a rotatable member, a plurality of resiliently expansible, internal shoe means normally adapted to partake of rotation of said member, said shoe means being cooperatively associated for relative movement within said rotatable member, and means adapted to restrain rotation of one of said shoe means whereupon said last named shoe means imposes a braking effect upon the rotatable member, another of said shoe means having floating movement relative to said first named shoe means upon imposition of its braking effect upon the member, and being automatically responsive to impose cumulative braking effect upon said member.

33. Braking mechanism comprising a rotatable member, a plurality of internal and expansible shoe means normally rotatable with said member, means cooperating with said shoe means to impose initial braking eifect upon the member, and means cooperating with the shoe means to automatically change the braking effect upon the member.

34. Braking mechanism comprising a rotatable member, a plurality of internal and expansible shoe means normally rotatable with said member, means cooperating with certain of said shoe means to impose initial braking effect upon the member, and means cooperating with the shoe means to automatically render other of said shoe means responsive to impose cumulative braking effect upon the member.

35. Braking mechanism comprising a rotatable member, expansible, internal shoe means normally rotatable with the member, means adapted to cooperate with the shoe means to impose initial braking effect upon the member, and means associated with the shoe means and automatically responsive to change the braking effect upon the member.

36. Braking mechanism comprising a rotatable member, internal and self-contained pressure shoe means normally rotatable with the member, and means adapted to cooperate with the shoe means to impose initial braking effect upon the member, said shoe means including means automatically responsive to initial braking effect to impose cumulative braking effect upon the member.

37. Braking mechanism comprising a rotatable drum having an annular braking surface, a pair of shoes in said drum, yieldable means biasing said shoes into engagement with said surface, said shoes being normally adapted to partake of the rotation of the drum, and means effective to control one of the shoes to impose initial braking effect upon the drum, the yieldable means being automatically effective to cause the other shoe to impose cumulative braking effect upon the drum.

38. In brake operating mechanism, comprising a drum, self -energizing brake shoe means and selfpressure action means for said shoe means in a I brake, in combination, a backing plate for the brake, a housing extending from the plate in the direction of the side thereof, an operating member slidable in the housing, and flying key means actuated by movement of said member into operating position for rendering the braking members effective to brake the drum.

39. In braking means, a brake drum, internal brake shoes resiliently held in contact with the drum and normally free to turn therewith, and means for locking the shoes against rotation.

40. In vehicle braking means, a brake drum, resiliently expansible shoe means for applying braking pressure to the drum and means for varying the applied pressure in accordance with variation in momentum of the vehicle, the effective area of contact between the pressure applying means and the drum being variable, a control member, and plurality of flying key means actuated by said member for varying the effective area of contact between the drum and the pressure applying means in accordance with movement of the control member.

41. In braking means, a drum, complementary internal friction members contacting the drum and normally free to turn therewith, and means optionally positionable to contact either of the friction members at a point thereof inwardly remote from the periphery of the drum for holding said friction member against rotation, the reaction incident to the rotation of the drum and the holding against rotation of the friction member tending to turn the adjacent portion of the friction member outwardly of the drum concentric with such point Aof contact and eccentric to but in the direction of rotation of the drum whereby the friction member exerts a wedging effect upon the drum for braking the latter.

42. In braking means, a drum, internal friction means contacting the drum and normally free to turn therewith, said friction means being noncontinuous, and means positionable to contact the friction means at a point adjacent one end thereof and inwardly remote from the periphery of the drum for holding the friction means against rotation whereby the portion of the friction means adjacent such point of contact tends to swing outwardly of the drum concentric with said point and eccentric to but in the direction of rotation of the drum thereby exerting a wedging effect upon the drum for braking the latter.

43. In braking means, a drum, internal friction means contacting the drum and normally free to turn therewith, and means for holding the friction means against rotation and for causing said friction means to exert a wedging effect upon the drum by the reaction incident to holding said friction means against rotation during continued rotation of said drum.

44. A brake comprising a rotatable drum having an annular braking surface, a series of several brake shoes in adjacent parallel planes within said drum, each of said series of brake shoes partaking of the rotary motion of said drum, and each of said series of brake shoes being disposed for free and unrestrained radial action upon said drum, and means effective to control each of said series of brake shoes independently, and successively, whereby the different braking action, of each of said series of brake shoes, imposes a braking effect of different intensity upon said drum.

45. In a brake, comprising a rotatable member having an annular surface, a plurality of independent and complete brake shoe means within said rotatable member, and partaking of the rotation thereof, each of said complete brake shoe means having within itself effective predetermined pressure applying means constrained between the members of the shoe means, said pressure applying means effecting continuous radial loading contact of said complete shoe means With the said annular braking surface of said rotatable 

